Particle and wave dynamics during plasma injections

Abstract

The SCATHA satellite measures particle and wave parameters as it moves outbound on the duskside from the plasmasphere into the plasma sheet. In many cases, plasma waves are not observed in the quiescent plasma sheet prior to a plasma injection. The electron distribution function prior to entry into the plasma sheet is a nearly isotropic soft spectrum, J(E) ∼ 1/E. Just inside the plasma sheet the spectrum begins to harden and becomes anisotropic, J⊥ > J∥. As the satellite penetrates deeper into the plasma sheet, the spectrum further hardens, especially near α0 ∼ 90°. At the injection the electron spectrum drastically hardens and often becomes peaked in the keV energy range. The pitch angle anisotropy is further enhanced in favor of J⊥. The plasma wave emissions onset occurred at the time of the injection. Whistler mode waves are observed below the electron cyclotron frequency. Electrostatic waves are detected in bands between the electron cyclotron frequency harmonics.